main(){
  var emp = {
    'ename': 'Tom',         //Key必须用引号括起来
    'age': 20
  };
  emp['salary'] = 50000;    //访问Map中的键值对只能使用“下标法”
  // print(emp.ename)       //编译时错误
  print("${emp['ename']}  ${emp['age']}  ${emp['salary']}");

  var product = new Map();
  product['pname'] = '可口可乐';
  product['price'] =  3.5;
  print(product);
}